for these types of shots a good prosumer digicam like yours is really a good way to go.. you get much closer working distances and more dof from the small sensors.. you would need quite an expensive dslr setup for these results..

I think most programs have a Map->Seemless tool. Anway, I use the GIMP (gimp.org). It's not as good as photoshop, but it's free. The less I spend on programs, the more I spend on cameras (my girlfriend thinks I spend it on her :blah. Anyway... look for it, I'm sure it's there. It's nice for when you have a somewhat random pattern that you want to tile.